To achieve a higher separation efficiency and reliability of electrostatic precipitators for suppression of high-ohmic dust is an important problem in the practice of removing suspended particles from gases by electrostatic precipitation. Because of the high electrical resistance of such dust most electrostatic precipitators used in power engineering, metallurgy, cement and chemical industries cannot provide for the required separation efficiency. At the same time frequent break-downs and a high rate of wear of the shaking mechanisms, while removing the layer of dust precipitated on the electrodes, affect the reliability and service life of electrostatic precipitators.
During the gas cleaning operation the dust particles are charged by the corona negative discharge produced in the interelectrode gap, that is between the corona-forming electrodes and precipitation electrodes, and are caused to deposit on the precipitation electrodes. When the specific electrical resistance of the dust to be removed is higher than 10.sup.8 Oh.m, a charge is accumulated under the action of the corona discharge current on the surface of the layer of dust so precipitated, while inside said layer an electric field is formed whose intensity becomes as high as 10 to 20 kv/ohm, which causes breakdowns in the dust layer. In this case in the breakdown regions on the precipitation electrodes there arise inverse corona discharges, wherefrom ions are emitted to the interelectrode gap, said ions having a polarity which is opposite to that of the corona-forming electrode. The positively charged ions neutralize a negative charge of the particles, thereby decreasing the charge or even inversing the polarity thereof, which in turn considerably decreases the velocity of the particles moving to the precipitation electrode and affects the separation efficiency.
The presence in the precipitator of an inverse corona discharge caused as a result of the drop of voltage across the layer of high-ohmic dust and the decrease of the electric strength of the interelectrode gap, the intensity of the electric field decreases, thereby decreasing the dust separation efficiency.
A high specific resistance of the high-ohmic dust is also responsible for the formation of a dust layer which is difficult to dislodge from the electrodes. Dislodging such a dust deposit requires a greater shaking impact force and a higher repetition frequency of shaking the electrodes. This affects the reliability of the shaking mechanisms in operation, and eventually impairs the dust separation efficiency as a whole.